We propose to study the long-term safety and efficacy of bilateral cingulotomy, a brain operation performed to relieve severe chronic pain and certain psychiatric disorders that are intractable to more standard therapies. The unique population that we shall study consists of 179 patients who underwent cingulotomy and participated in a prospective study conducted in our laboratory independently of the neurosurgeon. Patients were given rigorous psychiatric evaluations, neurological examinations, and neuropsychological assessments before and soon after operation. Early results indicated therapeutic benefits for a substantial proportion of patients in some diagnostic categories, without significant intellectual impairments. Considerable caution is desirable, however, in drawing conclusions about the value of a psychosurgical procedure. A meaningful evaluation requires a controlled, prospective study of the long-term benefits and dangers of the operation. The proposed follow-up study will permit such an evaluation by documenting, over the next 5 years, the long-term consequences of cingulotomy. We shall readminister all procedures given before and soon after operation in order to quantify changes in psychiatric, chronic pain, neurological, and neuropsychological status. In addition, we shall give new tests that tap the unknown contribution of the cingulate gyrus to human behavior. The combination of repeated and new methods of evaluation will allow us to answer in detail certain questions about the long-term safety and efficacy of cingulotomy and about the limbic system.